Merge pull request #103 from chrisliebert/master

Issue #74: Added basic diffuse texture support to examples/viewer

examples/viewer/viewer.cc

@@ -8,6 +8,7 @@
 #include <cstdlib>
 #include <iostream>
 #include <limits>
+#include <map>
 #include <string>
 #include <vector>
 
@@ -26,12 +27,24 @@
 
 #include "trackball.h"
 
+#define STB_IMAGE_IMPLEMENTATION
+#include "stb_image.h"
+
 #ifdef _WIN32
 #ifdef __cplusplus
 extern "C" {
 #endif
-#include <mmsystem.h>
 #include <windows.h>
+
+#ifdef max
+ #undef max
+#endif
+
+#ifdef min
+ #undef min
+#endif
+
+#include <mmsystem.h>
 #ifdef __cplusplus
 }
 #endif
@@ -112,6 +125,7 @@ class timerutil {
 typedef struct {
   GLuint vb;  // vertex buffer
   int numTriangles;
+  size_t material_id;
 } DrawObject;
 
 std::vector<DrawObject> gDrawObjects;
@@ -163,10 +177,11 @@ void CalcNormal(float N[3], float v0[3], float v1[3], float v2[3]) {
 
 bool LoadObjAndConvert(float bmin[3], float bmax[3],
                        std::vector<DrawObject>* drawObjects,
+                       std::vector<tinyobj::material_t>& materials,
+                       std::map<std::string, GLuint>& textures,
                        const char* filename) {
   tinyobj::attrib_t attrib;
   std::vector<tinyobj::shape_t> shapes;
-  std::vector<tinyobj::material_t> materials;
 
   timerutil tm;
 
@@ -194,17 +209,82 @@ bool LoadObjAndConvert(float bmin[3], float bmax[3],
   printf("# of materials = %d\n", (int)materials.size());
   printf("# of shapes    = %d\n", (int)shapes.size());
 
+  // Load diffuse textures
+  {
+      for (size_t m = 0; m < materials.size(); m++) {
+          tinyobj::material_t* mp = &materials[m];
+          
+          if (mp->diffuse_texname.length() > 0) {
+              // Only load the texture if it is not already loaded
+              if (textures.find(mp->diffuse_texname) == textures.end()) {
+                  GLuint texture_id;
+                  int w, h;
+                  int comp;
+                  unsigned char* image = stbi_load(mp->diffuse_texname.c_str(), &w, &h, &comp, STBI_default);
+                  if (image == nullptr) {
+                      std::cerr << "Unable to load texture: " << mp->diffuse_texname << std::endl;
+                      exit(1);
+                  }
+                  glGenTextures(1, &texture_id);
+                  glBindTexture(GL_TEXTURE_2D, texture_id);
+                  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+                  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+                  if (comp == 3) {
+                      glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, w, h, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
+                  }
+                  else if (comp == 4) {
+                      glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, image);
+                  }
+                  glBindTexture(GL_TEXTURE_2D, 0);
+                  stbi_image_free(image);
+                  textures.insert(std::make_pair(mp->diffuse_texname, texture_id));
+              }
+          }
+      }
+  }
+
   bmin[0] = bmin[1] = bmin[2] = std::numeric_limits<float>::max();
   bmax[0] = bmax[1] = bmax[2] = -std::numeric_limits<float>::max();
 
   {
     for (size_t s = 0; s < shapes.size(); s++) {
+      size_t current_material_id = 0;
+      if (shapes[s].mesh.material_ids.size() > 0 && shapes[s].mesh.material_ids.size() > s) {
+          // Base case
+          current_material_id = shapes[s].mesh.material_ids[s];
+      }
       DrawObject o;
       std::vector<float> vb;  // pos(3float), normal(3float), color(3float)
       for (size_t f = 0; f < shapes[s].mesh.indices.size() / 3; f++) {
         tinyobj::index_t idx0 = shapes[s].mesh.indices[3 * f + 0];
         tinyobj::index_t idx1 = shapes[s].mesh.indices[3 * f + 1];
         tinyobj::index_t idx2 = shapes[s].mesh.indices[3 * f + 2];
+        
+        current_material_id = shapes[s].mesh.material_ids[f];
+
+        if (current_material_id >= materials.size()) {
+            std::cerr << "Invalid material index: " << current_material_id << std::endl;
+        }
+        
+        float diffuse[3];
+        for (size_t i = 0; i < 3; i++) {
+            diffuse[i] = materials[current_material_id].diffuse[i];
+        }
+        float tc[3][2];
+        if (attrib.texcoords.size() > 0) {
+            assert(attrib.texcoords.size() > 2 * idx0.texcoord_index + 1);
+            assert(attrib.texcoords.size() > 2 * idx1.texcoord_index + 1);
+            assert(attrib.texcoords.size() > 2 * idx2.texcoord_index + 1);
+            tc[0][0] = attrib.texcoords[2 * idx0.texcoord_index];
+            tc[0][1] = 1.0f - attrib.texcoords[2 * idx0.texcoord_index + 1];
+            tc[1][0] = attrib.texcoords[2 * idx1.texcoord_index];
+            tc[1][1] = 1.0f - attrib.texcoords[2 * idx1.texcoord_index + 1];
+            tc[2][0] = attrib.texcoords[2 * idx2.texcoord_index];
+            tc[2][1] = 1.0f - attrib.texcoords[2 * idx2.texcoord_index + 1];
+        } else {
+            std::cerr << "Texcoordinates are not defined" << std::endl;
+            exit(2);
+        }
 
         float v[3][3];
         for (int k = 0; k < 3; k++) {
@@ -227,7 +307,6 @@ bool LoadObjAndConvert(float bmin[3], float bmax[3],
         }
 
         float n[3][3];
-
         if (attrib.normals.size() > 0) {
           int f0 = idx0.normal_index;
           int f1 = idx1.normal_index;
@@ -258,8 +337,14 @@ bool LoadObjAndConvert(float bmin[3], float bmax[3],
           vb.push_back(n[k][0]);
           vb.push_back(n[k][1]);
           vb.push_back(n[k][2]);
-          // Use normal as color.
+          // Combine normal and diffuse to get color.
-          float c[3] = {n[k][0], n[k][1], n[k][2]};
+          float normal_factor = 0.2;
+          float diffuse_factor = 1 - normal_factor;
+          float c[3] = {
+              n[k][0] * normal_factor + diffuse[0] * diffuse_factor,
+              n[k][1] * normal_factor + diffuse[1] * diffuse_factor,
+              n[k][2] * normal_factor + diffuse[2] * diffuse_factor
+          };
           float len2 = c[0] * c[0] + c[1] * c[1] + c[2] * c[2];
           if (len2 > 0.0f) {
             float len = sqrtf(len2);
@@ -271,17 +356,21 @@ bool LoadObjAndConvert(float bmin[3], float bmax[3],
           vb.push_back(c[0] * 0.5 + 0.5);
           vb.push_back(c[1] * 0.5 + 0.5);
           vb.push_back(c[2] * 0.5 + 0.5);
+          
+          vb.push_back(tc[k][0]);
+          vb.push_back(tc[k][1]);
         }
       }
 
       o.vb = 0;
       o.numTriangles = 0;
+      o.material_id = current_material_id;
       if (vb.size() > 0) {
         glGenBuffers(1, &o.vb);
         glBindBuffer(GL_ARRAY_BUFFER, o.vb);
         glBufferData(GL_ARRAY_BUFFER, vb.size() * sizeof(float), &vb.at(0),
                      GL_STATIC_DRAW);
-        o.numTriangles = vb.size() / 9 / 3;
+        o.numTriangles = vb.size() / (3 + 3 + 3 + 2) * 3;
         printf("shape[%d] # of triangles = %d\n", static_cast<int>(s),
                o.numTriangles);
       }
@@ -395,13 +484,13 @@ void motionFunc(GLFWwindow* window, double mouse_x, double mouse_y) {
   prevMouseY = mouse_y;
 }
 
-void Draw(const std::vector<DrawObject>& drawObjects) {
+void Draw(const std::vector<DrawObject>& drawObjects, std::vector<tinyobj::material_t>& materials, std::map<std::string, GLuint>& textures) {
   glPolygonMode(GL_FRONT, GL_FILL);
   glPolygonMode(GL_BACK, GL_FILL);
 
   glEnable(GL_POLYGON_OFFSET_FILL);
   glPolygonOffset(1.0, 1.0);
-  glColor3f(1.0f, 1.0f, 1.0f);
+  GLsizei stride = (3 + 3 + 3 + 2) * sizeof(float);
   for (size_t i = 0; i < drawObjects.size(); i++) {
     DrawObject o = drawObjects[i];
     if (o.vb < 1) {
@@ -412,12 +501,20 @@ void Draw(const std::vector<DrawObject>& drawObjects) {
     glEnableClientState(GL_VERTEX_ARRAY);
     glEnableClientState(GL_NORMAL_ARRAY);
     glEnableClientState(GL_COLOR_ARRAY);
-    glVertexPointer(3, GL_FLOAT, 36, (const void*)0);
+    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
-    glNormalPointer(GL_FLOAT, 36, (const void*)(sizeof(float) * 3));
+
-    glColorPointer(3, GL_FLOAT, 36, (const void*)(sizeof(float) * 6));
+    std::string diffuse_texname = materials[o.material_id].diffuse_texname;
+    if (diffuse_texname.length() > 0) {
+        glBindTexture(GL_TEXTURE_2D, textures[diffuse_texname]);
+    }
+    glVertexPointer(3, GL_FLOAT, stride, (const void*)0);
+    glNormalPointer(GL_FLOAT, stride, (const void*)(sizeof(float) * 3));
+    glColorPointer(3, GL_FLOAT, stride, (const void*)(sizeof(float) * 6));
+    glTexCoordPointer(2, GL_FLOAT, stride, (const void*)(sizeof(float) * 9));
 
     glDrawArrays(GL_TRIANGLES, 0, 3 * o.numTriangles);
     CheckErrors("drawarrays");
+    glBindTexture(GL_TEXTURE_2D, 0);
   }
 
   // draw wireframe
@@ -436,8 +533,11 @@ void Draw(const std::vector<DrawObject>& drawObjects) {
     glEnableClientState(GL_VERTEX_ARRAY);
     glEnableClientState(GL_NORMAL_ARRAY);
     glDisableClientState(GL_COLOR_ARRAY);
-    glVertexPointer(3, GL_FLOAT, 36, (const void*)0);
+    glDisableClientState(GL_TEXTURE_COORD_ARRAY);
-    glNormalPointer(GL_FLOAT, 36, (const void*)(sizeof(float) * 3));
+    glVertexPointer(3, GL_FLOAT, stride, (const void*)0);
+    glNormalPointer(GL_FLOAT, stride, (const void*)(sizeof(float) * 3));
+    glColorPointer(3, GL_FLOAT, stride, (const void*)(sizeof(float) * 6));
+    glTexCoordPointer(2, GL_FLOAT, stride, (const void*)(sizeof(float) * 9));
 
     glDrawArrays(GL_TRIANGLES, 0, 3 * o.numTriangles);
     CheckErrors("drawarrays");
@@ -498,7 +598,9 @@ int main(int argc, char** argv) {
   reshapeFunc(window, width, height);
 
   float bmin[3], bmax[3];
-  if (false == LoadObjAndConvert(bmin, bmax, &gDrawObjects, argv[1])) {
+  std::vector<tinyobj::material_t> materials;
+  std::map<std::string, GLuint> textures;
+  if (false == LoadObjAndConvert(bmin, bmax, &gDrawObjects, materials, textures, argv[1])) {
     return -1;
   }
 
@@ -516,6 +618,7 @@ int main(int argc, char** argv) {
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
     glEnable(GL_DEPTH_TEST);
+    glEnable(GL_TEXTURE_2D);
 
     // camera & rotate
     glMatrixMode(GL_MODELVIEW);
@@ -533,7 +636,7 @@ int main(int argc, char** argv) {
     glTranslatef(-0.5 * (bmax[0] + bmin[0]), -0.5 * (bmax[1] + bmin[1]),
                  -0.5 * (bmax[2] + bmin[2]));
 
-    Draw(gDrawObjects);
+    Draw(gDrawObjects, materials, textures);
 
     glfwSwapBuffers(window);
   }